US10022268B2 - Diaphragm-position-controlled, multi-mode ocular fluid management system and method - Google Patents

Abstract

Ocular fluid management systems and methods of operating the same. One ocular fluid management system includes a chamber, a diaphragm, a sensor, and a controller. The chamber includes a first portion and a second portion. The first portion is connected to an input line for receiving fluids into the first portion and an output line for discharging fluids from the first portion. The diaphragm is contained in the chamber and changes position based on a pressure difference between the first and second portions. The sensor detects a position of the diaphragm and transmits a signal based on the detected position. The controller is configured to receive the signal and control operation of at least one of a peristaltic pump and a vacuum pump based on the signal to maintain the diaphragm in a predetermined position.

Description

FIELD

Embodiments of the invention relate to ocular fluid management systems. More particularly, embodiments of the invention relate to a fluid management system that senses the position of a diaphragm and operates in one or more operating modes.

BACKGROUND

Fluid management systems, such as aspiration systems and infusion systems, are commonly used during ophthalmic procedures. An aspiration system removes fluids from a patient's eye. In contrast, an infusion system supplies fluids to the patient's eye. An integrated fluid management system provides both aspiration and infusion functions under common control. The operator can control the amount of pressure or suction applied by each system using a foot pedal, control panel settings, or a combination of both. However, particular situations occurring during a procedure require quick and efficient operation of the system, which may be difficult to perform manually. For example, if an aspiration system encounters a substance or obstruction that it cannot remove (e.g., a non-fluid substance or a dense substance), the obstruction often causes the aspiration system to lose proper suction. In this situation, the obstruction must be quickly and efficiently handled to resume proper operation of the aspiration system.

SUMMARY

Coordinated operation of the aspiration and infusion systems (as with an integrated fluid management system) is very important for patient safety. In modern ophthalmic surgical procedures, the eye is more or less a closed vessel (with some leakage). An excess of infusion over aspiration can cause an elevation of pressure in the eye, which can reduce perfusion of blood to the retina, among other consequences. An excess of aspiration over infusion can cause a reduction of pressure in the eye, and even collapse of certain structures. In the anterior chamber of the eye (between the cornea and the lens), collapse of the cornea and damage to the corneal endothelium with resulting opacity of the cornea are potential hazardous situations associated with improper pressure. In the posterior chamber of the eye (behind the lens), partial collapse of the globe, detachment of the choroid, and resulting hemorrhage are other serious situations associated with improper pressure.

At the very least, aspiration must not be allowed to occur if infusion is inactive. Therefore, means to ensure that infusion flow is always at least equal to aspiration flow (or slightly higher, to compensate for leakage) is highly desirable. In typical ophthalmic surgical systems, however, one or both of these flows is not measurable, so more indirect means are used to avoid hazardous situations. One object of certain embodiments of the invention is to provide an integrated fluid management system in which both the aspiration flow and the infusion flow can be determined.

Cataract surgery presents a particularly challenging situation. The procedure is performed inside of the anterior chamber of the eye. As noted above, excess of aspiration over infusion can lead to opacification of the cornea. The volume of the anterior chamber is very small, approximately 0.3 milliliters, so small imbalances in the fluid management system can quickly lead to a hazardous situation.

Cataract surgery is further complicated by the trend to use less ultrasonic power (to reduce potential injury) and to compensate by using higher vacuum levels in the aspiration system. In a typical procedure, aspiration is used to attract fragments of the lens to the tip of the surgical instrument. Once the lens fragment is firmly seated against the opening in the tip of the instrument (occlusion) the aspiration flow is obstructed and the vacuum level at the instrument tip increases. The combination of the increased vacuum and ultrasonic vibration of the instrument tip breaks up the lens material into fragments small enough to pass through the opening in the tip of the instrument (break of occlusion). With the aspiration path no longer obstructed, aspiration flow accelerates under the influence of the vacuum present. With the trend to use higher vacuum levels, this acceleration of flow (surge) is even more rapid and hazardous. Thus, an additional object of certain embodiments of the invention is to provide an aspiration system in which the break of occlusion surge is inherently limited to a volume less than the volume of the anterior chamber, e.g., less than 0.3 milliliters.

Aspiration systems used in ophthalmic surgery have been classified by the parameter (vacuum or flow) that is most directly controlled by the surgeon. Typically, the surgeon uses a proportional foot pedal control to vary the chosen parameter between zero and some maximum level that has been preset on the surgical system control panel.

Surgeons generally use a vacuum-controlled mode or a flow-controlled mode. The selected mode can be based on the type of surgical procedure being performed and/or surgeon preference. Earlier ophthalmic surgical systems were only capable of operating in one mode of aspiration control. Flow-controlled systems were typically used for cataract surgery and vacuum-controlled systems were typically used for vitreoretinal surgery. A recent trend is surgical systems in which the user can select either a vacuum-controlled mode of operation or a flow-controlled mode of operation. Some such systems have two completely separate aspiration systems (i.e., one of each type). Other systems do have means to operate a single aspiration system either as flow-controlled or as vacuum-controlled. However, such systems typically involve compromises, with one or both modes having lesser performance than an aspiration system dedicated to one mode of operation. One object of certain embodiments of the invention is to provide an aspiration system capable of operation in a flow-controlled mode, a vacuum-controlled mode, and new modes that have characteristics of both flow-controlled and vacuum-controlled modes.

Accordingly, embodiments of the invention provide systems and methods for controlling ocular fluid management systems. One fluid management system includes a chamber with a first portion and a second portion. A flexible diaphragm is contained in the chamber and changes position based on a pressure difference between the two portions. The system can operate in one or more modes and includes a system controller. Within each mode, a system controller automatically operates the system. In particular, in one or more of the modes, the system controller is configured to maintain the diaphragm in a predetermined position. In some embodiments, the system controller operates a peristaltic pump and a vacuum pump to maintain the diaphragm in the predetermined position. In some embodiments, the system controller is also configured to detect an occlusion break based on a position of the diaphragm.

In particular, one embodiment of the invention provides an ocular fluid management system. The system includes a chamber, a diaphragm, a sensor, and a controller. The chamber includes a first portion and a second portion. The first portion is connected to an input line for receiving fluids into the first portion and an output line for discharging fluids from the first portion. The diaphragm is contained in the chamber and is configured to change position based on a pressure difference between the first portion and the second portion. The sensor detects a position of the diaphragm and transmits a signal based on the detected position. The controller is configured to receive the signal and control operation of at least one of a peristaltic pump and a vacuum pump based on the signal to maintain the diaphragm in a predetermined position.

Another embodiment of the invention provides a method of operating an ocular fluid management system. The method includes receiving, by a controller, a signal from a sensor detecting a position of a flexible diaphragm contained in a chamber. The flexible diaphragm changes position based on a pressure difference between a first portion of the chamber and a second portion of the chamber. The first portion of the chamber is connected to an input line for receiving fluids into the first portion and an output line for discharging fluids from the first portion. The method also includes controlling, by the controller, at least one of a peristaltic pump and a vacuum pump based on the signal to maintain the diaphragm in a predetermined position.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a fluid management system and, more particularly, an aspiration system.

FIG. 2 schematically illustrates another embodiment of an aspiration system.

FIGS. 3-10 are flowcharts illustrating operation of the aspiration system ofFIG. 1 in various operating modes.

FIG. 11 is graph illustrating transitions between states of a vacuum control mode performed by the aspiration system ofFIG. 1.

FIG. 12 is graph illustrating transitions between states of a flow control mode performed by the aspiration system ofFIG. 1.

FIGS. 13-14 are graphs illustrating transitions between states of an occlusion response mode performed by the aspiration system ofFIG. 1.

FIG. 15 schematically illustrates an infusion system.

FIG. 16 schematically illustrates another embodiment of an infusion system.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected,” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc.

It should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative configurations are possible.

FIG. 1 illustrates afluid management system10. In many of the paragraphs that follow, thefluid management system10 is operated or configured as an aspiration system. However, as is also explained below, thesystem10 may also be operated or configured as an infusion system.

Thesystem10 includes achamber12. Aflexible diaphragm14 divides thechamber12 into a first portion16 (illustrated as portion “A” inFIG. 1) and a second portion18 (illustrated as portion “B” inFIG. 1). Thefirst portion16 is connected with an input oraspiration line20 that collects fluid from a patient's eye during a surgical operation. Thefirst portion16 of thechamber12 is also connected with apump22. In one embodiment, thepump22 is a peristaltic pump. In other embodiments, other pumping means may be used. Theperistaltic pump22 is connected to an output ordischarge line24. Fluid entering thechamber12 from theaspiration line20 exits thechamber12 through thedischarge line24, which empties into a collection bag (not illustrated).

A vacuum pump30 (or, more generically, a pressure regulator or pressure regulating means) is also connected to thechamber12. In particular, thevacuum pump30 is connected to thesecond portion18 of the chamber. A vacuum sensor32 (or, more generally, a pressure sensor) communicates with the chamber12 (e.g., with the second portion18). Thevacuum sensor32 provides a signal representing the vacuum level in the chamber12 (e.g., an amount of pressure in thesecond portion18 of the chamber12). The signal from thevacuum sensor32 is provided to avacuum controller34. Thevacuum controller34 uses the signal from thesensor32 to operate the vacuum pump30 (e.g., to establish a particular vacuum level in the chamber12). Accordingly, thevacuum sensor32 provides feedback to thevacuum controller34, and thevacuum controller34 uses the feedback to adjust the operation of the vacuum pump30 (e.g., by sending a vacuum command to the pump30). Thevacuum pump30 may be constructed using a peristaltic pump (distinct from the pump22), a sensor for sensing pressure level (which may be the sensor32), and a controller (such as the vacuum controller34).

As illustrated inFIG. 1, asensor36 detects a position of thediaphragm14 and outputs a signal representing the detected position of thediaphragm14. Thediaphragm14 changes position based on a pressure difference between thefirst portion16 and thesecond portion18. As discussed in greater detail, multiple possible positions of thediaphragm14 are illustrated inFIG. 1. Abarrier38 is also included in thechamber12 that limits motion of thediaphragm14 in at least one direction.

The position of thediaphragm14 is considered “limited” when thediaphragm14 is in contact with the barrier38 (see the dashedline40aillustrated inFIG. 1). A position of the diaphragm is considered “normal” when the diaphragm is stabilized close to its limited position but thediaphragm14 is not in contact with the barrier38 (see thesolid line40billustrated inFIG. 1). The volume displaced by the movement of thediaphragm14 from thenormal position40bto thelimited position40a(i.e., the volume gained in thefirst portion16 due to the movement of the diaphragm14) is called the “limited volume.” The other dashed lines illustrated inFIG. 1 represent two additional positions of thediaphragm14. For example, the straight dashedline40crepresents a “neutral” position of thediaphragm14, and the curved dashedline40drepresents a “maximum portion B volume” position.

The vacuum in thesecond portion18 of thechamber12 acts on theflexible diaphragm14 to draw thediaphragm14 toward thesecond portion18. The movement of thediaphragm14 causes an increasing vacuum level in the fluid in thefirst portion16 of thechamber12. An equilibrium is reached when the vacuum in thefirst portion16 of thechamber12 acts on thediaphragm14 with a force equal to the force exerted on the diaphragm by the vacuum in thesecond portion18 of thechamber12 minus any elastic force required to displace theflexible diaphragm14 from itsneutral position40c. If thediaphragm14 is highly flexible, this elastic force is small and the vacuum level in thefirst portion16 of thechamber12 will approximate the vacuum level in thesecond portion18.

The vacuum in thefirst portion16 of thechamber12 causes suction of fluid through theaspiration line20. Theperistaltic pump22 acts to remove fluid from thefirst portion16 throughdischarge line24. If and only if the outflow through thedischarge line24 equals the inflow through theaspiration line20, the volume of fluid in thefirst portion16 of the chamber will remain constant and the position ofdiaphragm14 will not change. Any imbalance between outflow and inflow will cause the position of thediaphragm14 to change over time.

As illustrated inFIG. 1, the signal output from thediaphragm position sensor36 is received at asystem controller42. As described in more detail below, thesystem controller42 uses the signal from thesensor36 and other feedback to operate thefluid management system10. Thesystem controller42 can also control theperistaltic pump22 by providing operating parameters to the pump22 (e.g., a pump speed and/or outflow rate). Similarly, thesystem controller42 can provide operating parameters to thevacuum controller34. As described in more detail below, in some embodiments, thesystem controller42 controls operation of theperistaltic pump22 and/or thevacuum pump30 to return and/or maintain the diaphragm at a predetermined position, such as thenormal position40b.

Forperistaltic pump22, there is a relationship between the rotational speed of the pump motor (e.g., RPM) and the flow through the pump (e.g., milliliters/minute). This relationship can be estimated from geometric considerations, or can be determined empirically. Thesystem controller42 typically has direct control over the rotational speed ofperistaltic pump22, but receives setpoint information or reports data in terms of flow. Besides rotational speed, angular position affects flow. In some embodiments, an average of flow over an entire rotation of theperistaltic pump22 is used for calculations by thesystem controller42. In other embodiments,system controller42 receives a signal fromangular position sensor43. In some embodiments, the motor drivingperistaltic pump22 is a stepping type andposition sensor43 provides an indexing pulse each time that the motor returns to a fixed position, thereby allowing angular position to be determined as the number of steps since the last indexing pulse. Based on the angular position information, a more exact relationship between rotational speed and flow can be calculated. In particular,system controller42 may adjust rotational speed in accordance with position so as to maintain a more nearly constant flow rate throughperistaltic pump22.

Thesystem controller42 receives input from an operator through auser interface44. The input can include an operating mode selection. The input can also receive operating parameters for a selected operating mode. Each operating mode of thefluid management system10 can be associated with one or more operating parameters. During operation, thesystem controller42 controls and monitors operation of thefluid management system10 based on the operating parameters. Additional details regarding the operating parameters are provided below. The operating parameters are typically set by an operator before an ophthalmic procedure. Thesystem controller42, however, can also receive real-time operating parameters from a user during an ophthalmic procedure, such as through a foot pedal.

It should be understood that thesystem controller42 can include additional components than those described herein. In addition, in some embodiments, the functionality of thesystem controller42 can be distributed among multiple systems or devices. Also, in some embodiments, the functionality of thesystem controller42 can be combined with other systems or devices. For example, in some embodiments, thesystem controller42 also performs the functionality of thevacuum controller34. In one such embodiment, the functions of thesystem controller42 and the vacuum (or pressure)controller34 are combined in a single controller that directly or indirectly receives signals from theposition sensor36 and thevacuum sensor32.

In a first state of operation (e.g., a vacuum-controlled state), thesystem controller42 responds to inputs through theoperator interface44 to set the vacuum setpoint.Vacuum controller34 operatesvacuum pump30 so as to maintain the output ofvacuum sensor32 at the vacuum setpoint level selected by the operator. Simultaneously, thesystem controller42 adjusts the pump speed ofperistaltic pump22 to maintain thediaphragm14 at a predetermined position, as determined by the signal from thediaphragm position sensor36. The pump speed can be used to calculate the outflow rate through thedischarge line24, which must be equal to the inflow rate through theaspiration line20. This assumed inflow rate may be displayed or otherwise used to affect the operation of the system.

In a second state of operation (e.g., a flow-controlled state), thesystem controller42 responds to inputs through theoperator interface44 to set the pump speed corresponding to a flow rate selected by the operator. Theperistaltic pump22 operates at this pump speed, thereby maintaining the outflow rate through thedischarge line24 at the selected flow rate. Simultaneously, thesystem controller42 adjusts the vacuum setpoint to vacuumcontroller34 to maintain thediaphragm14 at a predetermined position, as indicated by the signal from thediaphragm position sensor36. The inflow rate through theaspiration line20 should then be equal to the operator-selected outflow rate through thedischarge line24. The vacuum setpoint and/or the resulting actual vacuum signal from thevacuum sensor32 may be displayed or otherwise used to affect the operation of the system.

In either state of operation, occlusion of theaspiration line20 can result in a high applied vacuum and little or no flow. If the occlusion is abruptly removed, flow throughaspiration line20 will rapidly accelerate under the influence of the high vacuum. While both modes of operation have mechanisms to counteract this surge in inflow, there is a finite response time. Therefore, it is likely that there will be a temporary loss of control. As noted, uncontrolled aspiration flow is particularly hazardous in cataract surgery, where a surge of only 0.3 milliliters volume can result in collapse of the anterior chamber of the eye.

As illustrated inFIG. 1, thebarrier38 limits the movement of thediaphragm14 to the “limited” position shown as40a. The control mechanisms in either the first or second modes of operation (e.g., thevacuum controller34 and the peristaltic pump22) act to maintain thediaphragm14 in the “normal” position shown as40b. Thus, the maximum volume change during a loss of control situation (i.e., the volume change in thefirst portion16 of the chamber due to the movement of the diaphragm14) is the volume contained betweenposition40bandposition40aof the diaphragm. Based on the anatomy of the human eye, this “limited volume” should be designed to be less than 0.3 milliliters. However, the “limited volume” can be adjusted when embodiments of the invention are applied to different anatomies.

In some embodiments, thesystem controller42 may employ a third state of operation (e.g., a break of occlusion state) to return through theaspiration line20 some of the volume which may have been lost from the eye during the uncontrolled surge. The third state of operation is entered (from either the first or second state of operation) whenever there is a loss of control, as indicated by a change in the signal fromdiaphragm position sensor36 corresponding to a significant movement of the diaphragm fromposition40btowardsposition40a. In this third mode of operation, thesystem controller42 sets the vacuum setpoint at a predetermined low level and sets the pump speed of theperistaltic pump22 to a predetermined high speed in the reverse direction (causing flow through thedischarge line24 to be directed into thefirst portion16 of the chamber.) The third mode of operation is exited (to the previous mode of operation) after a period of time such that this reverse flow accumulates to a volume approximately equal to the “limited volume” discussed above. In either the first or second modes of operation, thesystem controller42 will then act to restore thediaphragm14 to the “normal”position40b.

FIG. 2 illustrates another embodiment offluid management system10. In this embodiment, thediaphragm position sensor36 is a non-contacting, optical-type sensor positioned to view thediaphragm14 through atransparent window100. Thetransparent window100 also serves as thebarrier38 and as part of the enclosure ofchamber12. In addition to peristaltic pump22 (connected throughdischarge line24 to collection bag106) thevacuum pump30 is also a peristaltic type pump. Thevacuum pump30 is connected to thesecond portion18 of thechamber12 and also to the atmosphere throughvent line102.Vacuum controller34 operatesvacuum pump30 bi-directionally. Pumping air from thechamber12 to thevent line102 increases the vacuum level in thesecond portion18 of the chamber, and pumping air from thevent line102 to thechamber12 decreases the vacuum level.Vacuum sensor32 communicates with thesecond portion18 of thechamber12 throughvacuum port104, providing a feedback signal to thevacuum controller34. Thefirst portion16 ofchamber12 is also connected throughaspiration line20 to various surgical instruments used in the patient's eye during a surgical operation.

Thesystem controller42 may be configured in a number of different ways and may include a processing unit50 (e.g., a microprocessor, an application specific integrated circuit (“ASIC”), etc.), one ormore memory modules52, and an input/output interface54. Thememory modules52 include non-transitory computer-readable medium, such as random-access memory (“RAM”) and/or read-only memory (“ROM”). Theprocessing unit50 can retrieve instructions from thememory modules52 and execute the instructions to perform particular functionality. Theprocessing unit50 can also retrieve and store data to thememory modules52 as part of executing the instructions.

Theprocessing unit50 can obtain data from devices and systems external to thesystem controller42 through the input/output interface54. For example, as noted above, thesystem controller42 receives signals from thediaphragm position sensor36 and theuser interface44. Thesystem controller42 also provides output to theperistaltic pump22 and thevacuum controller34. Therefore, the input/output interface54 connects thesystem controller42 to thediaphragm position sensor36, theuser interface44, theperistaltic pump22, and thevacuum controller34. It should be understood that thesystem controller42 can be connected to these and other devices external to thesystem controller42 using a wired connection or a wireless connection.

It should also be understood that thesystem controller42 can include additional components than those described herein. Furthermore, in some embodiments, the functionality of thesystem controller42 can be distributed among multiple systems or devices. Also, in some embodiments, the functionality of thesystem controller42 can be combined with other systems or devices. For example, in some embodiments, thesystem controller42 also performs the functionality of thevacuum controller34.

The instructions executed by theprocessing unit50 included in thesystem controller42 control operation of thefluid management system10. For example, in one embodiment, thefluid management system10 can operate in one of a plurality of modes. The instructions executed by theprocessing unit50 operate thefluid management system10 in one of the modes based on the manual selection of an operating mode by a user (e.g., through the user interface44). The instructions executed by theprocessing unit50 can also receive operating parameters for a selected operating mode from an operator (e.g., a surgeon) through theuser interface44. The instructions executed by theprocessing unit50 use the operating parameters and feedback to automatically operate thefluid management system10 within the selected operating mode. Furthermore, in some embodiments, the instructions executed by theprocessing unit50 automatically operate thefluid management system10 in a particular mode based on feedback received by thesystem controller42.

In some embodiments, thefluid management system10 operates in one of three operating modes: (1) a vacuum control mode; (2) a flow control mode; and (3) an occlusion response mode. An operator can manually select one of the modes before an ophthalmic procedure.FIGS. 3-10 are a flowchart illustrating operation of thesystem10 in each of the three modes. To allow the operator to select a particular mode, theuser interface44 displays a list of available operating modes (at block100) and the operator can select one of the operating modes before (or during) an ophthalmic procedure (at block102).

Pressure/Vacuum Control Mode

To operate thefluid management system10 in the vacuum control mode, an operator selects the vacuum control mode from the list of operating modes presented on the user interface44 (at block104). Theuser interface44 then prompts the operator to define operating parameters for the vacuum control mode (at block106). For the vacuum control mode, the operator specifies or selects a maximum vacuum level (V_max). The maximum vacuum level represents the maximum vacuum level achievable when the foot pedal is in a lowest (i.e., fully engaged) position. In some embodiments, the operator also defines a minimum vacuum level (V_min). In other embodiments, thesystem controller42 is preprogrammed or configured with a minimum vacuum level of zero. The minimum vacuum level represents the minimum vacuum level achievable when the foot pedal in a highest (i.e., minimally engaged) position. Thesystem controller42 derives a requested vacuum level (V_request) from the limits (V_{min and}V_max) and the position of the foot pedal between the minimally engaged and fully engaged positions. In some embodiments, the vacuum levels are specified in terms of millimeters of mercury (“mmHg”).

In some embodiments, the operator also defines a maximum outflow rate for the peristaltic pump22 (F_max) (e.g., in cubic centimeters per minute (“cc/min”)) as an operating parameter. In other embodiments, thesystem controller42 is preprogrammed or configured with the maximum achievable rate of theperistaltic pump22.

In some embodiments, theuser interface44 displays a list of available values for each operating parameter or a list of available sets of values for the set of operating parameters. Furthermore, in some embodiments, the list of available values is customized based on the operator (e.g., linked to an operator identifier provided by the operator to theuser interface44, such as when the operator logs into the system10).

In some embodiments, the vacuum control mode has two states:State1 and State2.State1 is the initial state. InState1, the operator can manually increase (or decrease) the vacuum level generated by thevacuum pump30 by increasing (or decreasing) pressure on the foot pedal. In particular, inState1, the operator operates the foot pedal to indicate a requested vacuum level (V_request). The manually-requested vacuum level is based on the maximum vacuum level and the current position of the foot pedal.

Thesystem controller42 receives the manually-requested vacuum level (at block107) and provides the requested vacuum level to thevacuum controller34. Thevacuum controller34 operates thevacuum pump30 using a closed feedback loop to maintain the vacuum in thesecond portion18 of thechamber12 at the requested vacuum level (at block108). An actual vacuum level (V_actual) is output by thevacuum sensor32, which is provided to thevacuum controller34 as feedback. In some embodiments, the actual vacuum level is also displayed on theuser interface44 or another display associated with thefluid management system10. During normal operation, the actual vacuum level will be close to the requested vacuum level, but, in some situations, there may be a time lag between when the vacuum level is requested and when the requested vacuum level is achieved.

DuringState1, thesystem controller42 also operates theperistaltic pump22 using a closed feedback loop to maintain thediaphragm14 in the normal position (at block110). A current diaphragm position is output by thesensor36, which is provided to thesystem controller42 as feedback.

If the actual outflow rate (F_actual) of theperistaltic pump22 rises to or exceeds the maximum outflow rate of the pump22 (F_max) during State1 (at block112), thesystem controller42exits State1 of the vacuum control mode and enters State2 of the vacuum control mode (seeFIG. 4). In some embodiments, there are two cases when the outflow rate of theperistaltic pump22 rises to the maximum outflow rate. One case includes a vacuum-cleaning procedure when the operator wants to aspirate small drops of liquid from the operating field at the maximum outflow rate. In this case, State2 of the vacuum control mode is prolonged and the operator disengages the foot pedal when the vacuum-cleaning procedure is finished. The other case occurs after an unusual event (e.g., a human error), such as when the maximum vacuum level is set too high for the aspiration system and the foot pedal is fully engaged. In this case, the duration of State2 of the vacuum control mode should be as short as possible and the operator should quickly disengage the foot pedal.

In State2 of the vacuum control mode, the operator operates the foot pedal to set a manually-requested vacuum level (atblock114,FIG. 4). However, as described in more detail below, the foot pedal does not control the vacuum level of thefluid management system10 during State2. Rather, the requested vacuum level is monitored to determine when to exit State2 of the vacuum control mode and return toState1.

During State2, thesystem controller42 operates theperistaltic pump22 using an open feedback loop to maintain the actual outflow rate of theperistaltic pump22 at the maximum outflow rate (F_max) (at block116). During State2, thesystem controller42 also maintains thediaphragm14 in the normal position using a closed feedback loop (at block117). In particular, thesystem controller42 uses the signal from thesensor36 representing the current position of thediaphragm14 as feedback to monitor the current position of thediaphragm14. Thesystem controller42 also transforms the current position of thediaphragm14 into a vacuum setpoint (V_setpoint) (at block118). As illustrated inFIG. 4, thesystem controller42 continues to reset the vacuum setpoint based on the current position of thediaphragm14 until State2 ends. Accordingly, during State2, the vacuum setpoint is used as the target vacuum level rather than the requested vacuum level initiated through the foot pedal. Therefore, as noted above, during State2, the foot pedal does not control the vacuum level.

Thesystem controller42 provides the vacuum setpoint to thevacuum controller34, and thevacuum controller34 operates thevacuum pump30 using a closed feedback loop to maintain the vacuum level in thesecond portion18 of the chamber at the vacuum setpoint (atblock120,FIG. 4). An actual vacuum level (V_actual) is output by thevacuum sensor32, which is provided to thevacuum controller34 as feedback (and can also be displayed on theuser interface44 as noted above). As noted above, the foot pedal does not control the vacuum level during State2 of the vacuum control mode. However, the requested vacuum level indicated by the foot pedal is monitored (at block114) and, when the requested vacuum level is less than or equal to the vacuum setpoint (at block122), thesystem controller42 exits State2 and returns toState1 of the vacuum control mode (atblock107,FIG. 3).

FIG. 11 illustrates transitions fromState1 to State2 (labeled as “S1→S2”) and from State2 to State1 (labeled as “S2→S1”) within the vacuum control mode when the operator conducts a vacuum-cleaning procedure.Curve130 represents the requested vacuum level (defined by foot pedal engagement).Curve132 represents the actual vacuum level in thesecond portion18 of thechamber12.Curve134 represents the vacuum setpoint set by thesystem controller42 during State2.Curve136 represents the actual outflow rate of theperistaltic pump22.Dots140 mark the trigger events for the transitions between the states.

Flow Control Mode

Returning toFIG. 3, to operate thefluid management system10 in the flow control mode, an operator selects the flow control mode from the list of operating modes presented on the user interface44 (at block150). Theuser interface44 then prompts the operator to define operating parameters for the flow control mode (atblock152,FIG. 5). For the flow control mode, the operator specifies or selects a maximum outflow rate (F_max) and a maximum vacuum level (V_max), as described above with respect to the vacuum control model. The maximum outflow rate represents the maximum outflow rate when the foot pedal is in a lowest (i.e., fully engaged) position. The maximum outflow rate can be specified in cubic centimeters per minute (“cc/min”).

In some embodiments, theuser interface44 displays a list of available values for each operating parameter or a list of available sets of values for the set of operating parameters. Furthermore, in some embodiments, the list of available values is customized based on the operator (e.g., linked to an operator identifier provided by the operator to theuser interface44, such as when the operator logs into the system10).

Similar to the vacuum control mode, in some embodiments, the flow control mode has two states:State1 and State2.State1 is the initial state. InState1, the operator can increase (or decrease) the outflow rate of theperistaltic pump22 by increasing (or decreasing) pressure on the foot pedal. In particular, the operator operates the foot pedal to indicate a requested outflow rate (F_request.). The manually-requested outflow rate is based on the maximum outflow rate and the current position of the foot pedal.

Thesystem controller42 receives the manually-requested outflow rate (at block154) and operates theperistaltic pump22 using an open feedback loop to maintain the outflow rate at the requested outflow rate (at block156). Thesystem controller42 also operates thevacuum pump30 using a closed feedback loop to maintain thediaphragm14 in the normal position (at block158). In particular, thesystem controller42 uses the signal from thesensor36 representing the current position of thediaphragm14 as feedback and provides operating parameters to thevacuum controller34 based on the current position of the diaphragm. Thevacuum controller34 operates thevacuum pump30 based on the received operating parameters. DuringState1, thevacuum sensor32 detects the actual vacuum level in thesecond portion18 of the chamber12 (at block160). As noted above, this value can be displayed to the operator. In addition, if the actual vacuum level rises to or exceeds the maximum vacuum level (at block162), thesystem controller42exits State1 of the flow control mode and enters State2.

In some embodiments, the vacuum level rises to the maximum vacuum level within the flow control mode when an occlusion occurs. As illustrated inFIG. 6, when thesystem controller42 detects an occlusion, thesystem42 generates a warning signal (at block164). The warning signal can include an audible and/or visual warning that informs the operator that an occlusion has been detected and that the operator should operate thefluid management system10 accordingly.

In State2 of the flow control mode, the operator operates the foot pedal to set a manually-requested outflow rate (atblock166,FIG. 6). However, as described in more detail below, the foot pedal does not control the outflow rate during State2. Rather, the requested outflow rate is monitored to determine when to exit State2 of the flow control mode and return toState1.

During State2, thevacuum controller34 operates thevacuum pump30 using a closed feedback loop to maintain the vacuum level in thesecond portion18 of the chamber at the maximum vacuum level (V_max) (at block168). In particular, thesystem controller42 provides the maximum vacuum level to thevacuum controller34, and thevacuum controller34 uses the signal from thevacuum sensor32 representing the current vacuum level as feedback. As noted above, the actual vacuum level can also be displayed to the operator.

During State2, thesystem controller42 also maintains thediaphragm14 in the normal position using a closed feedback loop (at block170). In particular, the signal from thesensor36 representing the current position of thediaphragm14 is used by thecontroller42 as feedback. Thesystem controller42 also transforms the current position of thediaphragm14 into an outflow setpoint (F_setpoint) (at block172). As illustrated inFIG. 3, thesystem controller42 continues to set the outflow setpoint based on the current position of thediaphragm14 until State2 ends. Accordingly, during State2, thesystem controller42 uses the outflow setpoint as the target outflow rate rather than the requested outflow rate initiated through the foot pedal. Therefore, as noted above, during State2, the foot pedal does not control the outflow rate.

During State2, thesystem controller42 also operates theperistaltic pump22 using an open feedback loop to maintain the outflow rate at the outflow setpoint (at block174). As noted above, the foot pedal does not control the outflow rate during State2 of the flow control mode. However, the requested outflow rate indicated by the foot pedal is monitored (at block166) and, when the requested outflow rate is less than or equal to the outflow setpoint (at block176), thesystem controller42 exits State2 and returns toState1 of the flow control mode (atblock154,FIG. 5).

FIG. 12 illustrates transitions fromState1 to State2 (labeled as “S1→S2”) and from State2 to State1 (labeled as “S2→S1”) within the flow control mode.Curve180 represents the requested outflow rate defined by foot pedal engagement.Curve182 represents the outflow setpoint set by thesystem controller42 in the State2.Curve184 represents the actual vacuum level in thesecond portion18 of thechamber12.Dots186 mark the trigger events causing the transition between the states.

Occlusion Response Mode

Returning toFIG. 3, to operate thefluid management system10 in the occlusion mode, an operator selects the occlusion response mode from the list of operating modes presented on the user interface44 (at block200). Theuser interface44 then prompts the operator to define operating parameters for the occlusion response mode (atblock202,FIG. 7). For the occlusion response mode, the operator specifies or selects a maximum outflow rate (F_max), an occlusion detection vacuum level (V_detect), and an occlusion hold vacuum level (V_hold). As described above for the flow control mode, the maximum outflow rate represents the maximum outflow rate when the foot pedal is in a lowest (i.e., fully engaged) position. The occlusion detection vacuum level represents a vacuum level used to detect an occlusion, and the occlusion hold vacuum level represents a vacuum level used after an occlusion is detected

The occlusion response mode has four states: State the operator can increase (or decrease) the outflow rate from theperistaltic pump22 by increasing (or decreasing) pressure on the foot pedal. In particular, the operator operates the foot pedal to indicate a requested outflow rate (F_request). The manually-requested outflow rate is based on the maximum outflow rate and the current position of the foot pedal.

DuringState1, thesystem controller42 receives the manually-requested outflow rate (at block204) and operates theperistaltic pump22 using an open feedback loop to maintain the outflow rate at the requested outflow rate (at block206). Thesystem controller42 also operates thevacuum pump30 using a closed feedback loop to maintain thediaphragm14 in the normal position (at block208). In particular, thesystem controller42 uses the signal from thesensor36 representing the current position of thediaphragm14 as feedback and provides operating parameters to thevacuum controller34 based on the current position. Thevacuum controller34 operates thevacuum pump30 based on the received operating parameters.

DuringState1, thevacuum sensor32 also detects the actual vacuum level in thesecond portion18 of the chamber12 (at block210). As noted above, this value can be displayed to the operator. In addition, if the actual vacuum level rises to or exceeds the occlusion detection vacuum level (V_detect) (at block212), thesystem controller42exits State1 of the occlusion response mode and enters State2.

In State2 of the occlusion response mode, the operator operates the foot pedal to set a manually-requested outflow rate (atblock220,FIG. 8). However, as described in more detail below, the foot pedal does not control the outflow rate during State2. Rather, the requested outflow rate is monitored to determine when to exit State2 of the occlusion response mode and return toState1.

During State2, thevacuum controller34 operates thevacuum pump30 using a closed feedback loop to increase and maintain the vacuum level in thesecond portion18 of thechamber12 at the occlusion hold vacuum level (V_hold) (at block224). In particular, thesystem controller42 provides the occlusion hold vacuum level to thevacuum controller34, and thevacuum controller34 uses the signal from thevacuum sensor32 representing the current vacuum level as feedback to raise the vacuum level to the occlusion hold vacuum level. As noted above, the actual vacuum level detected by thevacuum sensor32 can also be displayed to the operator. Maintaining the vacuum level at the occlusion hold vacuum level grasps the captured material (i.e., the obstruction) and, in some situations, frees or breaks the obstruction.

During State2, thesystem controller42 also maintains thediaphragm14 in the normal position using a closed feedback loop (at block226). In particular,system controller42 uses the signal from thesensor36 representing the current position of thediaphragm14 as feedback. Thesystem controller42 also transforms the current position of thediaphragm14 into an outflow setpoint (F_setpoint) (at block228). As illustrated inFIG. 8, thesystem controller42 continues to set the outflow setpoint based on the current position of thediaphragm14 until State2 ends. Accordingly, during State2, thesystem controller42 uses the outflow setpoint as the target outflow rate rather than the requested outflow rate initiated through the foot pedal. Therefore, as noted above, during State2, the foot pedal does not control the outflow rate.

During State2, thesystem controller42 also operates theperistaltic pump22 using an open feedback loop to maintain the outflow rate at the outflow setpoint (at block230). During State2, if thesystem controller42 detects a “break of occlusion” condition (at block232), thesystem controller42 exits State2 of the occlusion response mode and performs State3. In some embodiments, thesystem controller42 detects a “break of occlusion” condition based on signals from thediaphragm position sensor36. In particular, thesystem controller42 can be configured to detect a “break of occlusion” condition when rapid movement of thediaphragm14 toward the diaphragm's limited position is detected by thediaphragm position sensor36. In particular, when an obstruction is broken or removed, the diagram14 will experience a rapid fluctuation in position as pressure is released from thechamber12.

In State3, a break of the occlusion has been detected. Therefore, the high vacuum level that was used to grasp the obstruction is no longer necessary and, if maintained, could adversely affect the procedure. Accordingly, in State3, thesystem controller42 automatically controls thefluid management system10 to return thefluid management system10 to a state before the occlusion was detected (i.e., State1). In particular, as illustrated inFIG. 9, thesystem controller42 reverses operation of the peristaltic pump22 (at block240) until a volume equivalent to the limited volume is pumped back into thefirst portion16 of the chamber12 (at block242). Thesystem controller42 then stops the pump22 (at block244). In addition, thevacuum controller34 reverses thevacuum pump30 to drop the vacuum level in thesecond portion18 of thechamber12 below the occlusion detection vacuum level (e.g., based on operating parameters provided by the system controller42) (at block246). When the actual vacuum level drops below the occlusion detection vacuum level (at block248), thesystem controller42 exits State3 and returns toState1 of the occlusion response mode.

FIG. 13 shows transitions betweenState1 and State2 (labeled as “S1→S2”), State2 and State3 (labeled as “S2→S3”), and State3 and State1 (labeled as “S3→S1”) of the occlusion response mode.Curve250 represents the actual outflow rate.Curve252 represents the outflow setpoint set by thesystem controller42 in State2.Curve254 represents the actual vacuum level in thesecond portion18 of thechamber12.Dots256 mark trigger events that cause the transitions between the states.

Returning toFIG. 8, if a break of occlusion is not detected in State2 (atblock232,FIG. 8) but the requested outflow value (i.e., based on foot pedal pressure) is equal to or less than the outflow setpoint (at block260), thesystem controller42 exits State2 and performs State4 of the occlusion response mode. In State4, thefluid management system10 can be returned to normal operation (i.e., where no obstruction is detected) even if the “break of occlusion” condition was not detected. In particular, if there is only a partial obstruction and the available outflow rate is sufficient to satisfy the operator's outflow request (through the foot pedal), the occlusion response mode transitions to State4 where normal operation resumes. For example, as illustrated inFIG. 10, in State4, the operator can increase (or decrease) the outflow rate from theperistaltic pump22 by increasing (or decreasing) pressure on the foot pedal. In particular, the operator operates the foot pedal to indicate a requested outflow rate (F_request). The manually-requested outflow rate is based on the maximum outflow rate and the current position of the foot pedal.

During State4, thesystem controller42 receives the manually-requested outflow rate (at block262) and operates theperistaltic pump22 using an open feedback loop to maintain the outflow rate at the requested outflow rate (at block268). Thesystem controller42 also operates thevacuum pump30 in a closed feedback loop to maintain thediaphragm14 in the normal position (at block270). In particular, thesystem controller42 uses the signal from thesensor36 representing the current position of thediaphragm14 as feedback and provides operating parameters to thevacuum controller34 based on the current position. Thevacuum controller34 operates thevacuum pump30 based on the received operating parameters. During State4, thevacuum sensor32 also detects the actual vacuum level in thesecond portion18 of the chamber12 (at block272). This value can be displayed to the operator. In addition, if the actual vacuum level falls below the occlusion detection vacuum level (at block274), thesystem controller42 exits State4 of the occlusion response mode and returns toState1. If the actual vacuum level rises to the occlusion hold vacuum level (at block275),system controller42 exits State4 of the occlusion response mode and returns to State2.

FIG. 14 shows transitions betweenState1 and State2 (labeled as “S1→S2”), State2 and State4 (labeled as “S2→S4”), and State4 and State1 (labeled as “S3→S1”) of the occlusion response mode.Curve280 represents the requested outflow rate.Curve282 represents the actual outflow rate.Curve284 represents the outflow setpoint set by thesystem controller42 in State2.Curve286 represents the actual vacuum level in thesecond portion18 of thechamber12.Dots288 mark the occurrence of trigger events that cause the state transitions.

It should be understood that in some embodiments, thesystem controller42 is configured to automatically switch the operating mode of thefluid management system10 based on feedback received by thesystem controller42. For example, in some embodiments, when thesystem controller42 detects an occlusion, thesystem controller42 can be configured to automatically switch thefluid management system10 to the occlusion response mode (or a particular state of the occlusion response mode). Furthermore, it should be understood that thefluid management system10 can include additional modes than those described above and each operating modes described herein can include additional states than those described above.

Components of thefluid management system10 can also be used to control the infusion of fluids into the patient's eye. For example,FIG. 15 illustrates aninfusion system300. Similar to thesystem10, thesystem300 includes thechamber12 with the flexible diaphragm14 (and optionally the barrier38) and thesensor36 for detecting a position of thediaphragm14. Thesystem300 also includes theperistaltic pump22 and thesystem controller42 connected to theuser interface44. Analogous to the vacuum components in the aspiration system, the infusion system includes apressure pump330, apressure sensor332 and apressure controller334. Unlike thesystem10, thefirst portion16 of thechamber12 included in thesystem300 is connected with anoutput line302 that provides a fluid to the patient's eye during a surgical procedure. Thefirst portion16 of the chamber is also connected to asupply line304 that supplies the fluid to thefirst portion16 from an external fluid source (e.g., a bottle or bag of fluid). Accordingly, theperistaltic pump22 can be operated (e.g., using a control or foot pedal (not shown)) to control the amount and/or pressure of fluid drawn from the external fluid source (not shown) and supplied to the patient's eye.

Thesystem300 can be operated similar to thefluid management system10 described above. For example, thesystem300 can be operated in one or more different modes, and, in each mode, thesystem controller42 can be configured to operate thepump22 and/or thepressure pump330 to keep thediaphragm14 in a predetermined position. In particular, thesystem controller42 can use feedback loops that use feedback from thediaphragm position sensor36 to control the flow rate of theperistaltic pump22 and the gas pressure in thesecond portion18 to satisfy various surgical objectives (e.g., an increased infusion rate, a decreased infusion rate, a steady infusion rate, etc.). For example, thepressure pump330 is used to control the gas pressure in thesecond portion18 of the chamber. In thefluid management system10, the pressure in thesecond portion18 is maintained below ambient pressure to create a suction force that removes fluids from the patient's eye. Alternatively, in theinfusion system300, the pressure in thesecond portion18 is maintained above ambient pressure to create an output force for the fluids supplied to the patient's eye.

In a first mode of operation (pressure or vacuum control), thesystem controller42 responds to inputs through theoperator interface44 to set the pressure setpoint.Pressure controller334 operatespressure pump330 so as to maintain the output ofpressure sensor332 at the pressure setpoint level selected by the operator. Simultaneously, thesystem controller42 adjusts the pump speed ofperistaltic pump22 to maintain thediaphragm14 at a predetermined position, as determined by the signal from thediaphragm position sensor36. The pump speed can be used to calculate the inflow rate through thesupply line304, which must be equal to the outflow rate through theoutput line302. This assumed inflow rate may be displayed or otherwise used to affect the operation of the system.

In a second mode of operation (flow control), thesystem controller42 responds to inputs through theoperator interface44 to set the pump speed corresponding to a flow rate selected by the operator. Theperistaltic pump22 operates at this pump speed, thereby maintaining the inflow rate through thesupply line304 at the selected flow rate. Simultaneously, thesystem controller42 adjusts the pressure setpoint to pressurecontroller334 to maintain thediaphragm14 at a predetermined position, as indicated by the signal from thediaphragm position sensor36. The outflow rate through theoutput line302 should then be equal to the operator-selected inflow rate through thesupply line304. The pressure setpoint to pressurecontroller334 and/or the resulting actual pressure signal frompressure sensor332 may be displayed or otherwise used to affect the operation of the system.

In some embodiments, anaspiration system10 and aninfusion system300 are linked through acommon system controller42 to form an integrated fluid management system. In such a system, the operation of theinfusion system300 may be adjusted in real time to respond to changing conditions in theaspiration system10, so as to maintain a safe balance between fluids entering and leaving the eye. For example, the actual flow out of the eye derived from the operating parameters ofaspiration system10 might be used to set the flow into the eye (pump speed) for theinfusion system300 operating in the second mode of operation described above.

FIG. 16 illustrates another embodiment ofinfusion system300. Thediaphragm position sensor36 is a non-contacting, optical-type positioned to view thediaphragm14 through atransparent window100. Thetransparent window100 also serves as part of the enclosure ofchamber12. In addition to peristaltic pump22 (connected throughsupply line304 and vented administration set402 to fluid bottle404) thepressure pump330 is also a peristaltic type pump. Thepressure pump330 is connected tosecond portion18 of thechamber12 and also to the atmosphere throughvent line102.Pressure controller334 operatesperistaltic pump330 bi-directionally. Pumping air from thevent line102 to thechamber12 increases the pressure level in thesecond portion18 of thechamber12, and pumping air from thechamber12 to thevent line102 decreases the pressure level.Pressure sensor332 communicates with thesecond portion18 of thechamber12 throughpressure port406, providing a feedback signal to pressurecontroller334. Thefirst portion16 ofchamber12 is also connected throughoutput line302 to various surgical instruments used in the patient's eye during a surgical operation.

The embodiment shown inFIG. 16 also incorporates a fail-safe feature to ensure that at least some minimum level of infusion pressure is maintained at all times. The one-way valve408 is connected to permit flow fromsupply line304 tooutput line302.Fluid bottle404 is suspended above the level of thechamber12 such that the pressure (due to gravity) delivered through the vented administration set402 to thesupply line304 is at a level adequate to maintain the pressure in the eye at a minimum safe level. In the event thatperistaltic pump22 fails to operate, the pressure level inoutput line302 will fall as the fluid inchamber12 is used up. At the point where this pressure level falls to the same level as the pressure insupply line304, one-way valve408 will open and fluid flow to the eye will be maintained at that pressure level

In yet another embodiment, various features and aspects of embodiments described above may be combined to form an integrated ocular fluid management system. The system can include a first chamber having a first portion and a second portion. The first portion is connected to a first input line communicating with the first portion of the first chamber and a first output line communicating with the first portion of the first chamber. The system may also include a second chamber having a first portion and a second portion. The first portion is connected to a second input line communicating with the first portion of the second chamber and a second output line communicating with the first portion of the second chamber.

A first pump communicates with the first output line and a second pump communicates with the second input line. A first pressure regulator communicates with the second portion of the first chamber and has a range of operation including pressures less than ambient. A second pressure regulator communicates with the second portion of the second chamber and has a range of operation including pressures greater than ambient. A first diaphragm is contained in the first chamber and configured to change position based on a pressure difference between the first portion and the second portion of the first chamber. A second diaphragm is contained in the second chamber and is configured to change position based on a pressure difference between the first portion and the second portion of the second chamber. A first sensor detects a position of the first diaphragm and transmits a first signal based on the detected position. A second sensor detects a position of the second diaphragm and transmits a second signal based on the detected position. A first controller is configured to receive the first signal and control operation of at least one of the first pump and the first pressure regulator based on the first signal to maintain the first diaphragm in a predetermined position. A second controller is configured to receive the second signal and control operation of at least one of the second pump and the second pressure regulator based on the second signal to maintain the second diaphragm in a predetermined position.

The integrated ocular fluid management system may also include a third controller to coordinate the operation of the first controller and the second controller. Alternatively, the integrated ocular fluid management system may include a unified controller that encompasses the functions of the first, second, and third controllers.

The first controller may be configured to determine a break of occlusion condition. The first controller may also be configured to communicate the break of occlusion condition to at least one of the second and third controllers.

The second controller may be configured to respond to a break of occlusion condition by commanding the second pressure regulator to set a predetermined pressure in the second portion of the second chamber based on a pressure level in the fluid management system. The second controller may also be configured to respond to a break of occlusion condition by commanding the second pressure regulator to set a predetermined pressure in the second portion of the second chamber greater than a normal operating pressure. The third controller may have multiple modes of operation including at least one mode of operation in which the second controller is coordinated to operate the second pump to maintain the flow in the second input line at a level equal to or greater than the flow in the first output line that the first controller maintains by operation of the first pump.

Various features and aspects of the invention are set forth in the following claims.

Claims (17)

What is claimed is:

1. An ocular fluid management system, comprising:

a chamber including a first portion and a second portion, the first portion connected to an input line configured to receive fluids into the first portion of the chamber and an output line configured to discharge fluids from the first portion of the chamber;

a pump communicating with at least one selected from the group consisting of the input line and the output line;

a pressure regulator communicating with the second portion of the chamber;

a diaphragm contained in the chamber and configured to change position based on a pressure difference between the first portion and the second portion of the chamber;

an optical sensor disposed outside of the chamber and configured to detect a position of the diaphragm and transmit a signal based on the detected position;

a transparent barrier located between the diaphragm and the optical sensor, wherein the transparent barrier limits movement of the diaphragm in a direction of the second portion of the chamber and the transparent barrier limits displacement of the diaphragm into the second portion of the chamber to a volume less than 0.3 milliliters; and

a controller configured to receive the signal and control operation of at least one of the pump and the pressure regulator based on the signal to maintain the diaphragm in a predetermined position.

2. The system ofclaim 1, wherein the pump is configured to maintain a predetermined flow rate.

3. The system ofclaim 2, wherein the pump comprises a peristaltic pump.

4. The system ofclaim 3, wherein the pump further comprises an angular position sensor.

5. The system ofclaim 4, wherein a peristaltic pump angular speed is adjusted on the basis of an angular position.

6. The system ofclaim 3, wherein the pressure regulator comprises a peristaltic pump.

7. The system ofclaim 1, wherein the pump communicates with the output line and a range of operation of the pressure regulator includes pressures less than ambient pressure.

8. The system ofclaim 7, wherein the controller has at least one mode of operation in which the pressure regulator is operated to maintain a predetermined pressure level and the pump is operated to maintain the diaphragm in the predetermined position.

9. The system ofclaim 7, wherein the controller has at least one mode of operation in which the pump is operated to maintain a predetermined flow and the pressure regulator is operated to maintain the diaphragm in the predetermined position.

10. The system ofclaim 1, wherein the pump communicates with the input line and a range of operation of the pressure regulator includes pressures greater than ambient pressure.

11. The system ofclaim 10, wherein the controller has at least one mode of operation in which the pressure regulator is operated to maintain a predetermined pressure level and the pump is operated to maintain the diaphragm in the predetermined position.

12. The system ofclaim 10, further comprising a one-way valve connected between the input line and the output line so as to permit flow when pressure in the output line is less than pressure in the input line.

13. The system ofclaim 1, wherein the controller is configured to determine a break of occlusion condition when the diaphragm position signal indicates a rapid, uncontrolled displacement toward the transparent barrier.

14. The system ofclaim 13, wherein the controller is configured to respond to the break of occlusion condition by reversing the direction of the pump to inject a predetermined volume of fluid into the first portion of the chamber.

15. The system ofclaim 14, wherein the volume of fluid injected into the first portion of the chamber is predetermined based on a maximum displacement of the diaphragm limited by the transparent barrier.

16. The system ofclaim 13, wherein the controller is configured to respond to the break of occlusion condition by commanding the pressure regulator to set a predetermined pressure in the second portion of the chamber.

17. An ocular fluid management system, comprising:

a chamber including a first portion and a second portion, the first portion connected to an input line configured to receive fluids into the first portion of the chamber and an output line configured to discharge fluids from the first portion of the chamber;

a peristaltic pump having an angular position sensor and communicating with at least one selected from the group consisting of the input line and the output line;

a pressure regulator communicating with the second portion of the chamber;

a diaphragm contained in the chamber and configured to change position based on a pressure difference between the first portion and the second portion of the chamber;

an optical sensor configured to detect a position of the diaphragm and transmit a signal based on the detected position;

a transparent barrier located between the diaphragm and the optical position sensor, wherein the transparent barrier limits movement of the diaphragm in a direction of the second portion of the chamber and the transparent barrier limits displacement of the diaphragm into the second portion of the chamber to a volume less than 0.3 milliliters; and

a controller configured to receive the signal and control operation of at least one of the peristaltic pump and the pressure regulator based on the signal to maintain the diaphragm in a predetermined position.

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